The US Environmental Protection Agency (EPA) has asked the White House to review the new engine and fuel standards for the largest ocean-bound ships.
The draft aims to cut air pollution nationwide by requiring vessels with large diesel engines to curb nitrogen oxide and sulphur dioxide emissions.
The EPA has also proposed to forbid the US production and sale of high-sulphur marine fuel.
The EPA is under a legal deadline to finalise the rule by 17 December and the standards for newly built engines would be applied in early 2011 while long-term standards would begin in 2016.
In March, the US and Canada has asked the International Maritime Organization (IMO) to designate thousands of miles of the countries’ coastlines as emission control areas.
The IMO is expected to review the request at its July 2010 meeting, and the designation would go into effect in 2012.